I could easily get a bunch of bluepill boards from taobao with 8~9 rmb(1.2 ~ 1.3 usd) for each(cheaper, smaller and way more powerful than arduino uno clones). so definitely....the bluepill wins for any geek projects, thanks to this community for the Arduino core

among the F1 i'm a die hard fan for MM (clone - from Baite) (the prejudice is because i simply have it)
among the F4 i agree with Ollie bluepad (stm32f407 mini) is about the most seductive (i've got a separate 'china made (possibly designed)' f405 the pins aren't properly broken out, while black stm32f407 has an oversized footprint